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PtilocercusThe pen-tailed tree-shrew (Ptilocercus lowii) was classified with other tree-shrews in the Family Tupaiidae, but has been placed in its own family, Ptilocercidae family.).
The body is 130-140 mm and the tail is 160-190 mm. The back is gray to light brown; the belly is white/yellowish belly. There are plume-like hairs on the latter 2/5ths of the tail. The "pen tail" is proximally black, fading to white distally. Individuals often have a black eye mask. The weight is 40-62 g (1.41-2.19 oz).
It lives in peninsular Thailand, Malaysia, Sumatra, northern Borneo and nearby small islands. It occurs in primary and secondary forests, rubber farms and in houses near forest edges. It is often associated with the palm tree Eugeissona tristis.
It is usually caught 1.5-2 m off the ground on vines and branches at altitudes from sea level to 2000 m (5). It is the only nocturnal tree-shrew. It is quite lethargic during the day and will often confront a human disturbance by turning on its back exposing the belly, hissing loudly and gaping widely, often urinating and defecating. It is energetic at night; if disturbed, it quickly runs away from its disturber (6). Communal nesting is suspected as groups of 2-5 are often found in nests (7), while captives will sleep together after a period of contact (6). Nests are constructed inside trees, lined with dried leaves, twigs, fibres of soft woods (7) and are about 76 mm (3 in) in diameter and 45 cm (18 in) long (8). Nests are made in large branches and tree trunks 12-20 m above the ground (7). Whittow and Gould (9) showed that oxygen consumption and body temperature dropped significantly during the day while sleeping. This drop in metabolic rate may be associated with energy conservation and possibly communal nesting. Like other tree-shrews, this species can walk on the underside of branches (6). Its tail is extremely sensitive to touch and is often used in displays like "tail wagging" (a pendulum-like motion) after aggressive encounters, or is held up straight showing excitement (6).
Like most tree-shrews, this species is an omnivore. It may eat bananas, grapes, crickets and grasshoppers (6), as well as black ants, cockroaches, beetles, earwigs, cicadas, leaf insects and young forest geckos (7). It is probably adept at capturing food (6). It is the only known wild mammal that chronically consumes alcohol. A study in Malaysia found that it spends several hours a night drinking naturally fermented nectar of the bertam palm with an alcohol content of up to 3.8%. It does not become intoxicated and may metabolise ethanol by a pathway that is not used as heavily by humans.
There are two pairs of teats. Litters of 1-4 young are probably born after 45-55 days and weigh about 10 g (0.35 oz)(10). The tree-shrew may live for 2.7 years.
The pen-tail tree shrew is classed as Least Concern on the IUCN Red List and is on Appendix II of CITES (http://members.vienna.at/shrew/itsesAP95-cover.html). It is threatened by habitat fragmentation and destruction, such as slash-and-burn clearing of tropical forests for cultivation and human use.